Field of the Invention
Embodiments of the present invention relate generally to computer science and, more specifically, to techniques for modelling elastic rods in position-based dynamics frameworks.
Description of the Related Art
Generating realistic simulation results in real-time is essential for animating three-dimensional objects in time-sensitive animation applications, such as game engines. Position-based dynamics (PBD) frameworks are well-suited to many such animation applications. Notably, PBD frameworks employ techniques that sacrifice some quantitative accuracy to generate visually plausible results in real-time. For example, in PBD frameworks, all deformations of objects are characterized with discrete positions of points.
While the tradeoffs exhibited by PBD frameworks are often acceptable, some types of animation are not adequately represented in PBD frameworks. In particular, because PBD frameworks specify positions but not angles, PBD frameworks are typically unable to simulate complex bending and twisting of objects modeled as rods. Such a restriction limits the applicability of PBD frameworks to animation. For example, while PBD frameworks successfully animate much of a human body, PBD frameworks are typically unable to realistically simulate the twisting of curly hair.
Accordingly, elastic rods are commonly simulated using force-based methods, such as the finite element method, that are not optimized to represent deformations as only positions. While such force-based methods are capable of effectively emulating the natural motion of curly hair, the time required to simulate the thousands of hair strands included in a typical head of hair using force-based methods is prohibitive and unsuitable for animation-oriented applications.
As the foregoing illustrates, what is needed in the art are more effective techniques for simulating bending and twisting of elastic rods.